Thomas h



March 27, 1928. 1,664,185

T. H. RODMAN v BRAKING SYSTEM FOR MOTOR DRIVEN MACHINERY Filed Oct. 25,1922 INVENTOR.

Elke mm HRodma/n ATTORNEY Patented Mar. 27, 1928.

UNITED STATES THOMAS H. acumen, or NEW YORK, n. Y.,

ASSIGNOR TO THE CIITIIERHAMMER MFG.

60., OF MILWAUKEE, WISCONSIN, 'A COHTPORATIONOF \VISCONSIN.

BRAKING SYSTEM FOR MOTOR-DRIVEN MACHINERY.

Application filed October 25, 1922. Serial No. 596,706.

This invention relates to braking systems for motor driven machineryOperating on alternating current.

\Vhile not limited thereto, the invention is particularly applicable tohigh speed 'printing presses.

In practice it is very desirable to prov de high speed printing presseswith braking means exerting a braking force approx mately directlyproportional to the kinetic energy of the machine for quick and smoothstopping thereof. Also it is highly desirable to render the press whenidle free from braking action.

An object of the present invention is to provide a braking systemapplicable to printing presses and other machinery operating onalternating current which will have the aforementioned desiredcharacteristics.

Another object is to adapt to such machinery the braking systemdisclosed in the Henderson Patent No. 1,252,902,- granted January 8,1918.

In the system disclosed in the Henderson patent aforementioned, aplurality of electromechanical brakes are provided for differentcylinders of the press, said brakes being of the normally released typeand being responsive to current generated by the D. C. press drive whendisconnected from circuit and driven by the press. Further the brakesare of a type adapted when so energized to subject the press to abraking force approximately directly proportional to the 85 kineticenergy of the press and according to the present invention it ispreferred to employ similar brakes and to provide a supply of directcurrent simulating that afforded by the driving machine in such formersystern.

One embodiment of the present invention is diagrammatically illustratedin the accompanying drawing and the same will now be described it beingunderstood that the embodiment illustrated is susceptible of variousmodifications without departing from the scope of the appended claims.

In the accompanying drawing,

Figure 1 is a diagrammatic view of the braking system; and

Fig. 2 is a sectional view of a preferred form of electromagnetic brake.

Referring to the drawing the same illustrates a printing press of thedeck type having a plurality of couplets 1 to be driven by an A. C.motor 2 and to be braked by individual electromagnetic brakes 3'refcrably of the type shown in Fig. 2. is to be tilltfielsifitkl thatthe printing press couplets l and motor 2 are merely shown as typical ofany desired machine and drive therefor and that the brakes 3 need not beof the specific type illustrated. As will be understood a brake of thetype illustrated may be de-. signed for a. braking effect thereofapproximately directly proportional to the square of the currentsupplied thereto and the brake preferably so designed.

The motor is shown as supplied with current from an A. (3. line L, 11,11 through an electron'iagnetic switch 5 to be controlled in anysuitable manner, said switch having auxiliary contacts 6 to complete theenergizing circuit of a relay 7 when the motor 2 is disconnected fromcircuit. The cnergizing; circuit for relay 7 extends from line L byconductor 10 through the winding of said relay by conductor 11 to andthrough the contacts 6 of switch 5 when said switch is open by conductor12 to line L.

The relay 7 which is of the normally open type controls the continuityof circuit between the windings of brakes 3 and a supply generator 13therefor, the latter having its armature a driven by motor 2 or directlyby the machine 1 as preferred. As will be observed a circuit extendsfrom the right hand terminal of the generator 13 by conductor 1 1through relay 7 by conductor 15 to and through the brake windings inseries by conductor 16 to the left hand terminal. of the generator.

The generator 13 is separately excited, its field being supplied by asmall motor generator set 18 supplied with current from the A. C. lineL, L L Hence the voltage output of the generator 13 is renderedapproximately dircctly proportional to the speed of motor 2.

Thus assuming operation of motor 2 to drive machine 1 release of switch5 to disconnect motor 2 from the circuit will energize relay 7 tosubject the windings of brakes 3 to a direct current whose voltage isapproximately directly proportional to the speed of motor 2 andmachine 1. This current closely simulates the braking current of theHenderson system aforementioned. and accordingly causes the brakes toapply with an eifcct approximately directly pro-- portionalf tothevkinetie energg of the ma chlne. Moreover; When' the-Inael11ne 1 andmotor 2 are brought to rest the generator ply" of currentrt o the brakesandconsequent eifect-ing release of the brakes.

by Letters Patent is:

1. In a braking systemsifor motorrdriven' machines operatlng' onalternating current voltagelfis approximateiyi "zclire'ctly' proportionaleto the speed ofsaidwmachinew 2.:. In rabraking systemwfor -motordriveni machines fopera'lting' ion 1 alternating current i incombination direct current ibnaki'ngsgneans 20 to *produce a braking"effect approximately proportional to the square of the current 13 .is'arrested thereby.,terminating ,thei-sup supplied thereto-and .asuppLygeneratnniox;

. S3101" brakwhichlis drivenby saidlinachine and which has means toseparately excite its fieldxL I v p 3. In a braking system for motordriven machines operatinguom alternating current; in combination, directcurrent electro-mechan ical brakihg meansto produce-a braking effectapproximately: proportional to they:

square of the current supplied;theretogezamizn means to supply saidannamzwithidi rect' current'"Whosewoltageq us approximate-e lyproportional to the speed 0-sadl1m1achmer 3 In 'witnessnvhereof, *rIshame whersnmisubscnbe'd'rmyanamem THQMAS HnRODMAN'L-r,

